If a quadratic equation has a discriminant that equals zero, which of the following statements is always true?

a. the equation has two solutions and the parabola will open upward.
b. the equation has one solution and the parabola will open downward.
c. the equation has zero solutions and there is not enough information to determine the direction of the parabola.
d. the equation has one solution and there is not enough information to determine the direction of the parabola.

d. The equation has one solution and there is not enough information to determine the direction of the parabola.

Step-by-step explanation:

For a general quadratic equation

y = ax² +bx +c

the solution is

The discriminant (D) is the part of the quadratic formula underneath the radical: b² - 4ac.

D tells us whether there are

If D= 0,

and there are two identical solutions ("one solution").

The direction of the parabola depends on the sign of a.

That information is not given, so we cannot determine the direction of the parabola.

answer: all of the odd numbers were opened

the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.

the answer is b